[x-bird2]

seems like you really do need to get return lines down to the pan off the heads. if the accusump dumps its load you've got that much extra oil in the system for a few moments and it sounds like the oil pump is getting it up top faster than it can come back down--add in the extra and the top end is overloaded. the returns would also likely help prevent it from kicking in as often. In regards to a period-correct dry sump, does it have to be pontiac specific? Plenty of F1-F2-sports racers of that era ran dry sumps.

[Skip Fix]

Might think of some restricted pushrods, although the oil on the top end helps cool the valve springs for those extended runs compared to a drag car.

When I started autocrossing with slicks I started slinging oil out the TH350 vent and had to extended it. Slicks are fun but throw stuff around with the added G forces.